The Catholic Church in Malaysia, Singapore and Brunei (its two small Malay neighbors) is composed of a Latin Church hierarchy, joint in the transnational Episcopal Conference of Malaysia, Singapore and Brunei, consisting of three ecclesiastical provinces in Malaysia, a non-metropolitan archdiocese for Singapore, and a pre-diocesan Apostolic Vicariate for Brunei.
There is an Apostolic Nunciature to Malaysia as papal diplomatic representation (embassy-level) in the national capital Kuala Lumpur.
In it the Apostolic Delegation (lower level) to Brunei is also vested.
There is a separate Apostolic Nunciature to Singapore (in the capital of the same name), into which are vested the Non-Residential Pontifical Representation for Vietnam and Apostolic Nunciature to the Association of Southeast Asian Nations (ASEAN, which all abovementioned states belong to, with others in the region).
All defunct jurisdictions have current successor sees.